Aircraft rely on airfoils to create aerodynamic lift by creating a difference in pressure above and below the airfoil. On most airfoils, the upper surface is longer than the lower surface, thereby, causing faster airflow above the wing. This results in a lower pressure above the airfoil which causes lift. Generally, airfoils designed for slow flight have a larger upper surface in proportion to the lower surface which creates more lift, but also more drag. Airfoils that are designed for faster flight have a smaller upper surface in proportion to the lower surface and create less drag. High speed airfoils (See FIG. 1) require more power and do not perform well at low speeds.
At higher angles of attack (AOAs) separation of a boundary layer of air begins to occur at the aft upper section of the wing. The shape of the airfoil determines where, how, at what speed, and how abrupt this separation is. Once the critical AOA is reached, the airfoil will stall.
Blown wing resultant from induced airflow changes the relative airflow and can increase the allowable AOA from relative motion of the wing. This configuration requires higher power states to drive air over the airfoil with sufficient velocity to increase lift and inhibit boundary layer separation.
A glider airfoil is another solution. A wing with a long wingspan and short chord (fore and aft), allows for slower speeds. Additional system components such as dihedral wings, stall strips, and winglets are all aimed at achieving a balance between desired lift, stall, drag, and performance.
What is needed is an airfoil method and system that can adapt to various conditions which will maximize efficiency during low and high speed conditions. Essentially, a method and system that will combine the advantages seen in FIGS. 1A and 1B while minimizing the drawbacks.